Section 4D.17 Visibility,
Shielding, and Positioning of Signal Faces
[Excerpt from existing text of Section 4D.17]:
Standard:
The use of a signal backplate for target value enhancement should be considered on signal faces viewed against a bright sky or bright or confusing backgrounds.
Support:
The use of backplates enhances the contrast between the traffic signals and their surroundings for both day and night conditions, which is also helpful to elderly drivers.
[Recommended Addition of new Option]:
Option:
A yellow retroreflective strip no wider than 75 mm (3 in) may be placed around the perimeter of the face of backplates to project a rectangular appearance at night.